Historically, the classical metronome has been a mechanical pendulum device which creates a beat as it swings back and forth at a tempo which is adjusted by positioning a weight on the pendulum arm. This early type of metronome usually includes a calibrated scale whereby the weight position will indicate the set tempo. Due to physical limitations, this type of indicating means is restricted to coarse frequency indications.
Early mechanical metronomes have given way to electro-mechanical devices wherein the tempo is chosen by setting a dial on the instrument. This device is also limited by the physical dimensions of the dial so that only coarse tempo selections may be made over a relatively broad range.
Neither of the above types of metronomes have the capability of measuring the tempo produced by other means. One such device is in existence which can provide an indication of tempo and that is the tempowatch created by Cecil Effinger of Boulder, Colo. This is a stop watch with a recalibrated face. A user activates the stop watch at the beginning of a beat and allows the watch to run for six beats and then stops the watch. The recalibrated face then provides a reading in beats per minute. This device provides no other indication of tempo nor will it produce a tempo.
The relatively simple metronome and beat determining devices have been duplicated to varying extents by electronic means utilizing contemporary technology. For instance, the features found in the simple mechanical or electro-mechanical metronome may be found in electronic metronomes such as the type typlified by U.S. Pat. No. 4,018,131 issued to R. L. Cannon on "Electronic Metronome". This device is a variable oscillator in combination with a speaker wherein the oscillatory circuit is adapted to provide periodic impulses to the speaker at a beat recurrent frequency rate within the normal metronome range of 40 to 208 beats per minute.
U.S. Pat. Nos. 4,014,167; 4,090,355; 4,204,400; and 4,218,874 on "Electronic Metronome" issued to R. Hasegawa et al; F. Morohoshi; F. Morohoshi et al and S. Ishida et al respectively are more elaborate adaptations of the concept presented in Cannon wherein an oscillator provides a beat output via an amplifier to a loud speaker and the beat repetition rate is controlled either by controlling the oscillator frequency or incorporating a variable divider between the oscillator and amplifier circuitry.
P. Watkins, U.S. Pat. No. 4,193,257 on "Programmable Metronome" advances the state of the art by providing a plurality of variable rate time pulse generators which may be used to activate different sound generating devices so that up and down beats may be produced. Watkins offers the further improvement of providing a digital indication of the cadence but the device is limited in that only a few cadences are available for selection.
T. Sasaki et al, U.S. Pat. No. 4,213,372 on "Electronic Type Music Learning Aids" incorporates contemporary technology to provide a means whereby musical information may be entered into a storage means in a digital fashion and extracted therefrom in the form of a visual display and tone.
All of the prior metronome systems, as exemplified by the foregoing, fail to provide an accurate metronome wherein an exact cadence or repetition rate may be selected via a digital keyboard and indicated via a digital readout means or selected by playing a one beat interval manually on the metronome, after which the metronome automatically repeats the cadence and provides a digital indication of the beat frequency.